Fluid-pressure brake



INVENTOR CLYDE CFARMER www ATTORNEY Patented Jan. v31 y 1928.

UNITED STATES 1,657,530 `Pa'r'lezu'r OFFICE.

CLYDE C. FARMER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR T THE WESTING- HOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIAl FLUID-PRESSURE BRAKE.

Application led April 15, 1926. Serial No. 102,220.

This invention relates to fluid pressure brakes, and more particularly to the brake control equipment on the locomotive.

F or controlling the fluid pressure brakes on a train, the locomotive is `provided with a brake valve device, having a running position, in which fluid under pressure is supplied to the brake pipe through a feed valve device, to maintain the pressure in the brake pipe at a predetermined degree. The brake valve device Valso has a release position, in which `fluid under pressure is supplied directly from the main reservoir to the brake pipe in order to ett/'ect the release ci' the brakes.

In case lof a sudden reduction in brake pipe pressure, the brakes are applied -in emergency, and the reduction in brake pipe pressure is serially propagated throughout the train by the well known quick serial action, produced by locally venting fluid from the brake pipe on each car of the train.

If the sudden reduction in brake pipe pressure is initiated at a point in the train other than by operation of the brake valve device, the brake valve will ordinarily be in running position, in which fiuid is supplied to the brake pipe, and while the above emergency action to apply the brakes will occur, it the engineer does not promptly move the brake valve handle to lap position, so as to cut oii the flow of fluid to the brake pipe,

. the brakes on the car at the headof the train and on the llocomotive are liable to be released, by the continual flow of `fluid to the brake pipe. i

The principal object of my invention is to provide means for automatically cutting 0E the flow of iiuid to the brake pipe at the brake valve when an emergency reduction in brake pipe pressure is produced, in order lto prevent the .release of the brakes.

In the accompanying drawing, the single figure is a diagrammatic view, with the principal parts in section, of a locomotiveV brake apparat-us embodying my invention.

The apparatus shown in the drawing includes a brake valve device 1, a quick action vent valve device 2, a lcontrol valve device 3, and a iiuid pressure supply :cut-ott valve device 4.

The brake valve device 1 comprises a casv ing having a valve chamber' 5 containing the usual rotary valve 6 adapted to be operated by handle 7. Included in the brake valve casing is the usual equalizing discharge valve mechanism comprising a piston 8 having the .chamber 9 at one side connected to an equalizing reservoir 10 and the chamber 11 at the opposite side connected to the brake pipe 12. Piston 8 is adapted to operate a discharge valve 13 for venting Huid from the brake pipe 12.

The supply cut-oit valve device 4 is preterably incorporated in the brake valve device and comprises ay valve piston 14 havinga stem 15 connected toa guide member 16. The chamber 17 at one side ci' the valve piston 14 is connected to a pipe 18 leading to the control valve device 3 and chamber 19 at the opposite `side is connected to a passage 20 which leads ,tov the seat oit' rotary valve 6. In the normal position, as shown in the drawing, the chamber 19 is open to a chamber 21 which is connected to a passage 22 `leading to the brake pipe 12.

The `control valve device 3 comprises a ncasing having a `piston chamber 23 contain ing a piston 24 and connected by a passage 25 containing a check valve `26 to a pipe 27, leading to the `vent valve device 2. Valve chamber 28 at the opposite side of piston 24 contains a slide valve 29 adaptedto be operated by piston 24 and is connected to a pipe 3() to which fluid under pressure is supplied by .operation of the usual feed valve dcvice 31.

The `vent valve device 2 comprises a casing having a piston chamber `32 containing a piston 33 and a, valve chamber 34; con

taining a slide valve adapted to be operated by piston 33. The quick action venting portion ofthe ventval-ve'device com prises .a piston 36 contained in piston chamber 37 and a vent valve 38 contained in valve chamber 39 and adapted to be operated by piston 36. i f

In operation, the brake pipe 12 being connected with a passage 41 in the vent valve j device 2, which leadsto valve chamber 39, and valve chamber 39 being connectedby passage 42 to piston chamber 32, said piston chamber is subject to brake pipe pressure. From piston chamber 32, `iiuid flows through passage 43 to valve chamber 34, and the fluid pressures on `opposite sides of piston 33 being lthus equalized, spring 44e' maintains the piston and kslide valve 35 in the normal position, as shown in the drawing.

In this position, slide valve blanks passage 45, leading to piston chamber 37 and piston chamber 37 being open tothe atmospheric port 4G, through restricted port All in piston 86, the piston chamber and pipe 2 are maintained at atmospheric`V pressure, and opposite sides ot' piston 36 being` at atmospheric pressure, the brake pipe pressure acting in valve chamber 39 on valve 38, holds said valve seated. l

The piston chamber 23 of the control valve device 3' open to the atmosphere through a restricted port 48, and since atmospheric pressure is present in pipe 27, the pis ton chamber Q3 will be maintained at atmosplieric pressure, so that fluid at leed valve pressure, as supplied through pipe 30 to valve chamber 28, acts on piston 24;, to mainw tain same in the right hand position, as shown in the drawing.

In this position, pipe 18 is connected, through a cavity 49 in slide valve 29 with an atmospheric exhaust port 50, so that pis ton chamber 17 ot the supply cutcd valve device 4 is new subject to fluid at atmos pheric pressure, so that fluid at brake pipe pressure supplied to chamber 2l, acts to maintain the valve piston la in its outer position, as shown. ln this position, commu nication between passages 20 and 22 is open and thus fluid at the pressure supplied by the il'eedvalve device 3l, tlovvs through passage 5l and cavity 52 in rotary valve (i, to passage Q0 and thence through passage 22 to the brake pipe 12, thus maintaining the pressurein the brake pipe at the pressure Vof fluid supplied by the feed valve device, in

the usual manner.

It' a sudden reduction in brake pipe presn sure should occur somewhere in the train, the brake pipe pressure in piston chamber 32 of the vent valve device 2V on the locomotive will be reduced and piston 33 will he shifted to its outer position by the pressure ,of fluid in valve chamber 34. Passage l5 is connected to valve chamber `3l by the corre spending movement Voll slide valve 35, so that fluid under pressure is supplied from said valve chamber to piston chamber 37. Piston 36 is then actuated by the fluid under pressure so supplied, so as to open the vent valve 38 and thereby eliect a local vent ing of fluid from the brake pipe- 12to the exhaust port 46.

f Fluid under pressure supplied to piston chamber 37 flows through pipe 2T to piston `chamber 23 of the control valve device 3 and `this pressure, assisted by spring 53 actuates piston 2a, and moves slide valveQQ so that cavity 54 connects pipe 18 With a `pipe 55, leading to the main reservoir 56.`

Fluid at main reservoir pressure is then supplied to piston chamber 17 of the cut-olli valve device 4 and valve piston 14 is thereby actuatedso asto cut olf communication between passages Q0 and 2Q and thus prevent the flow ol? lluid l'roin the feed valve device 3l to the hralre pipe l2. `lt will thus be Seen that the apparatus operates :.uitomatically upon a sudden reduction in brake pipe pressure to cut oli' the ilow oil ll'luid to the brake pipe regardless or the position or the brake valve handle.

VCavity 5a in slide valve Ell) also connects passage with pipe 55, so that lluid at main reservoir pressure is supplied to piston chamhertS-S and operates to maintain piston 2l in its inner position, regardless of the venting of lluid from said piston chamber by way or the restricted vent port 4:8.

Check valve 26 prevents hach flow from piston chamber :23 to pipe 27, which might otherwise tiovv through passage` l5 to the seat or slide valve 35 and tend to blow the slide valve oli its seat. i

ln order to permit the release of the brakes alter an emergency application of the hralrcs, a reset cocli 5T is interposed in lthe passage 25 having an operating handle 58. When the handle 58 is turned from its normal position, communication through passage 25 is cut oll, so that fluid under pressure is prevented 'trom flowing from the main reservoir 56 to the piston chamber 23. The pressure in said piston chamber then quickly blows down through the port 48, permitting the lluid pressure in valve chaluber 28 to shilt piston '2a to its outer normal position, in which pipe 11.8 is again connected to exhaust port 50. VValve piston '14; is con- `secpiently shifted outwardly by the fluid pressure acting in chamber' 21, so that communication is again established between passages :20 and lWith thebrale valve handle in release or running position, the brake pipe will be charged with `fluid under pressure in the usual manner, so as to eilect the release or the brakes. Y

lllfhen the handle 58 is released, a spring 59 operates thereon, to shift the handle back to its normal position.

Havingnoiv described my invention, what I claim as new and desire to secure by Letters Patent, is

l. In a lluid pressure brake, the combination with a brake pipe and a brake valve device lor controlling a communication througlrwhich fluid under pressure is supplied to the brake pipe, of a cut-oil valve device operated by tluid under pressure tor closing said communication, a control valve device operated bylluid under pressure for supplying fluid to said cut-olf valve device, and means operated upon a sudden reduction in bralre pipe pressure for supplying fluid under pressure to said control valve device.

2. In a fluid pressure brake, the combinag tion with a brake pipe and a brake valve device fr :l'or controlling. aV communication device having means for supplying fluid under pressure to the brake pipe, of a valve device operated upon an increase in fluid under pressure for cutting olf co1nniunication through which fluid is supplied from the brake valve device to the brake pipe, and means Operated upon a Sudden reduction in brake pipe pressure for supplying fluid under pressure to said valve device.

In testimony whereof I have hereunto s t n hand.

e 1y GLYDE C. FARMER. 

